Retrievable bridge plug



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-i UTV im M. B. CONRAD ec. E2, i967 RETRIEVABLE BRIDGE PLUG 5 Sheets-Sheet b Filed Aug. 3, 1965 United States Patent O 3,357,493 RETREVABLE TLRHDGE PLUG Martin E. Conrad, 9326 Rives Ave., Downey, Calif. 90240 Filed Aug. 3, 1965, Ser. No. 476,828 20 Claims. (Cl. T66-122) ABSTRACT F THE DISCLOSURE A retrievable bridge plug including a body having a passage therethrough with spaced sealing members on the exterior and a combined friction means and anchor -between the seals. A valve is included at either end of the passageway through the body, while a third valve cooperates with ports providing communication with the exterior of the body between the seals. An actuating rod operates the valves, while the third valve includes a pressure area biasing it to a closed position in response to liuid pressure within the body.

This invention pertains to a retrievable bridge plug for use in oil wells or the like.

The device of this invention provides a bridge plug that can be positioned in a well in a desired location, which can plug the well for allowing various operations to take place, and subsequently can be removed. This bridge plug is superior to previous bridge plug designs in its reliability, resistance to pressures from above or below, and simplicity and versatility of operation.

In general, the unit includes an outer tubular body assembly through which extends a rod which can be moved axially a limited distance relative to the tubular unit. A valve circumscribing the rod can seal olf the interior from the top, while a second valve can close the bottom end of the unit. Downward movement of the rod relative to the tubular assembly will open the upper valve, while the lower valve can be opened by upward shifting of the rod. Within the central portion of the bridge plug is a third valve that cooperates with radial ports through the tubular assembly. This valve is normally biased -by a spring to a closed position, but also can be operated selectively by the rod to shift to the open position at appropriate times. The central valve includes a piston area through which internal pressures urge this valve upwardly toward its closed position. This, in turn, holds the rod in its upper position relative to the tubular assembly so that the rod is prevented from being moved downwardly by pressures above the bridge plug. This piston area in the bridge plug used to help hold the rod upwardly means that the rod will be maintained in a raised position relative to the tubular body even when the pressure from above is higher than the pressure below that location. This keeps the rod from opening the upper valve and allowing the interior of the bridge plug to fill with sand.

Through the cooperation provided between the rod and the third valve, various important functions are achieved. The rod always opens the central valve first when the tool is being run into the well. This equalizes the pressure between the packing elements above and below the valve so that the tool can move into the well without a possible unbalanced condition. In the latter condition, forcing movement of the bridge plug in the well causes an objectionably high rate of wear at the packing cups. Also, as noted above, pressures within the tool will hold the central valve in a closed position to resist higher pressures from above that otherwise would cause the rod to open the upper valve. Furthermore, when the central valve is open it allows pressures to vent through from the top or 3,357,493 Patented Dec. 12, 1967 ice the bottom, depending upon where the pressures are higher. This occurs prior to opening the top valve by the rod because the parts are arranged so that when the rod is moved inwardly the top valve is moved to an open position only after the central valve has been opened.

Another feature of the design of this invention is the use of a friction holding means to position the plug within the well, instead of relying upon pressure buttons or the common arrangement of slip cones. Such previously used devices inherently rely upon retaining elements that must be embedded in the wall of the well and absorb forces in shear that are imposed upon the plug. They include teeth that must be kept sharp, and their effectiveness is governed -by the material adjacent and its hardness. Moreover, there is the possibility of breakage or jamming of the parts that can prevent removal of the plug. The friction holding arrangement used in connection with this invention, however, has none of these drawbacks and will secure the plug in any location against extremely high forces tending to dislodge it.

The bridge plug of this invention will be frictionally held in place wherever it is positioned in the well. Additionally, the anchoring arrangement will react to fluid pressures from above or below to lock the bridge plug securely. Moreover, the plug can be pumped up, trapping an internal pressure, in which condition it will resist eX- ternal pressures both from above and below without opening up to allow sanding. When so pressurized from the interior, neither the upper nor the lower valve will be opened by the pressure above or below the plug up to very high values. In fact, it will withstand pressures as great as the internal pressure from above, and a substantial portion of internal pressure from below without the valves being opened.

The plug of this invention also is arranged to give a positive indication signal of its location when it is to be found and moved. The head at the upper end of the plug allows the retrieving tool to engage the body of the plug upon downward movement relative to the plug. The plug then absorbs the tubing string load and prevents further appreciable downward movement. This is because the plug is held in position either fromV compression of the fluid in the hole beneath the plug that causes the anchor to grip the well casing, or from previous locking of the plug by internal pressure. This tattletale signal gives assurance that the plug has been located and an attachment can be made for moving it.

An object of this invention is to provide -a bridge plug of improved reliability, versatility and overall performance.

Another object of this invention is to provide a bridge plug that can be retrieved safely under virtually all conditions.

An additional object of this invention is to provide a bridge plug incorporating a friction retaining means allowing it to be anchored securely in place while assuring also that the retaining means can be released without danger of failure in the locked position.

A further object of this invention is to provide a plug that will remain in any position where it is left, and will hold against pressure from either end.

A still further object of this invention is to provide a bridge plug having a selectively operable central valve to permit pressure balancing between the packings and venting from above or below.

Another object of this invention is to provide a bridge plug having top, bottom and central valves selectively operable by the rod extending through the tubing string.

An additional object of this invention is to provide a bridge plug that can be internally pumped up and will resist high pressures above and below it without the interior of the plug being opened.

Yet another object of this invention is to provide a bridge plug incorporating an improved friction drag and holding means that can secure it in any desired location in the well.

A further object of this invention is to provide a bridge plug that will give a positive tattletale signal indicating its location in a well.

A still further object of this invention is to provide a bridge plug in which internal pressures are used to hold the rod in a raised position so that it will not be moved downwardlyv to open the upper valve.

These and other objects will become apparent from the following detailed description taken in connection with the accompanying drawings in which:

FIGURE' 1A is a longitudinal sectional view of the upper portion of the bridge plug of this invention positioned in a well casing, with the valves in the closed position;

FIGUR-EIB is a longitudinal section-al view of the lower portion of the bridge plug in a position similar to that of FIGURE 1A;

FIGURE 2 is a perspective view of the central valve element separated from the remainder of the unit;

|FIGURE 3 is an enlarged transverse sectional view taken along line 3--3 of FIGURE 1A, illustrating the friction anchor device;

FIGURE 4 is a perspective view of the outer slotted sleeve of the friction anchor unit;

FIGUREv 5 is a perspective view of the inner slotted sleeve of the friction anchor unit;

FIGURE 6 is a fragmentary side elevational view of the outer slotted sleeve in its expanded position for heat treatment;

FIGURE 7 is a View similar to FIGURE 6, but with the sleeve contracted a maximum amount;

FIGURES l8A and 8B are views similar to FIGURE lA and 1B, respectively, with the parts in the positions assumed as the bridge plug is being run into the well;

FIGURES 9A and 9B are views similar to FIGURES 1A and 1B, respectively, with the parts in the position assumed as the bridge plug is being removed from the well;

FIGURE l0 is a fragmentary longitudinal sectional view showing the heat at the upper end of the rod, with the retrieving tool engaging the upper end of the body of the plug;

FIGURE 11 is a perspective view of the head removed from the other components of the device;

FIGURE 12 is a schematic view of the dat pattern of the J-slot in the head; and

FIGURE 13 is a fragmentary perspective view, partially broken away of the lower end of the means for moving the plug in the well.

As shown in the drawing, the bridge plug of this invention isreceived in a well casing 11 in the conventional manner. Extending the length of the tool at its axis is a rod 12 which is used to raise and lower the bridge plug 10. At the upper portion of the rod 12 are radially projecting flanges 13, which lit into wide axially extending slots 14 in a tubular member 15. The latter element is the topmost of a series of tubular members connected together in forming a tubing string that is the outer body portion of the bridge plug. Hence, the member 15 threads into a second tubular element 16, being sealed with respect to the inner wall of that member by an O-ring 17. The lower portion of the tubular member 15 includes an inwardly convergent frustoconical section 18 beneath which is an outwardly flaring frustoconical portion 19. The latter part of the tube 15 forms a seat for a first valve member 20. A resilient sealing element 21 is provided in the tapered surface of the valve that is adapted to engage the seat 19.

The valve 20 can iioat with respect to the other parts of the bridge plug, being an annular element that circumscribes the rod 12 beneath a shoulder 22 formed on the rod. The valve 20 can slide axially on the rod, and is sealed with respect to it by an O-ring 23. A collar 24 is provided on the rod 12 beneath the valve 2t), and a compression spring 2S bears against the upper edge of the collar 24. The opposite end of the spring 25 engages the undersurface of the valve member 26, biasing the valve to a closed position against the seat 19, this beingthe position of FIGURE'IA.

The lower end of the tubular member 16 connects by screw threads to an additional tubular member 27, being sealed at the joint by an O-ring 28. A packing 29 of elastomeric material, such as synthetic rubber, fits around the member 27. This packing is cup-shaped in the conventional manner, including a recess 30 in its upper end that rcceives a short sleeve 31. The upper end of the packing 29 flares outwardly to engage the well casing 11. The bottom of the tubular member 16 engages the upper edge of the sleeve 31, holding the packing 29 in position. The bottom end of the packing 29, in turn, bears against an additional backing sleeve 34 of elastomeric material, which is positioned adjacent the shoulder 35 on the tubular member 27 and also is engaged by the upper end of an annular threaded ring 36. The packing 29 is sealed with respect to the exterior of the tubular member 27, which is accomplished through the inclusion of an annular metal insert 37 that is grooved to receive an O-ring 38.

At its lower end, the member 27 threads into an additional tubular member 40, which is the next in the tubing string forming the bridge plug of this invention. The member 4)` includes a plurality of radial ports 41 providing communication between the interior of the bridge plug and its exterior beneath the packing 29. An annular slide valve 42 can effect closing of the ports 41 when the device is positioned as shown in FIGURES l-A and 9A.

The valve element 42, seen in perspective in FIGURE 2, includes an annular shoulder 43 engageable with the lower radial end surface of the tubular member 27 when the valve is in the closed position. It includes also a pair of O-rings 44 and 45 which are located on either side ofthe ports 41 when the valve is closed so that there is no com,-

munication with the ports, and the interior of the bridge plug 10is sealed at that location. Four flanges 47 extend radially inwardly at the upper end of the valve member 42 and on their upper surfaces 48 can engage a shoulder 49 formed in the lower section of the tubular member 27. At their inner edges, the iianges 47 are notched to provide shoulders 50 that are engageable with a shoulder 51 defined by the bottom radial surface of a collar 52 for-med on the rod 12.

The lower end of the valve 42 is engaged by a relatively strong compression spring 53, the opposite end of which bears against a shoulder S4 formed in the tubular member 40. The spring 53, therefore, biases the valve to its upper` position of FIGURES 1A and 9A where the ports 41` are closed. It should be noted that the valve member 42 aliects only the radial ports 41, and does not block the interior ofthe bridge plug. There is a space 55 between adjacent flanges 47 of the valve 42 so that fluid can iiow through the annular valve member 42, regardless of its axial position.

Beneath the valve 42 is the anchor assembly 56 that provides the drag and friction locking means for the retrievable bridge plug of this invention. The unit E6 includes a sleeve 57 of a flexible elastomer, circumscribing the tube 40. The sleeve 57 includes a 4bead 5S at its upper end retained by a shoulder 59 of a collar 6'3, the latter member being sealed by an O-ring 61 with respect to the exterior of the tube 40. Similarly, at the bottom end of the sleeve 57 is a bead 62 retained by a shoulder 63 of a collar 64 that may -be identical to the collar 60.

Around the flexible sleeve 57 is a pair of slotted metal sleeves 66 and 67, shown in perspective and separated from the remainder of thc assembly in FIGURES 4 and 5. The inner sleeve 66 is of constant wall thickness and provided with a plurality of axially aligned slots 68 extending inwardly from the bottom end 69 and stopping just short of the upper end 70. Intermediate the slots 68 are simllar slots 71 that extend from the upper end 70 to a point adjacent the bottom end 69.

The inner sleeve 66 is closely fitted into the outer sleeve 67 that includes axial slots 73 and 74 extending axially in from its bottom and top ends 75 and 76, respectively. The slots 73 and 74 correspond in length and size to the slots 68 and 71 of the inner sleeve 66. A dowel pin 77 carried by the inner sleeve 66 extends into the upper portion of one of the slots 73 to maintain the slots in the two sleeves 66 and 67 in a staggered relationship. In other words, the slots 68 and 71 in the sleeve 66 are not in registry with the slots 73 and 74 of the outer sleeve 67, but fall in between the slots in the outer sleeve. This prevents extrusion of the flexible inner sleeve 57 through the slotted outer sleeve when the interior of the bridge plug is pressurized, as explained more fully below.

The outer sleeve 67 is of greater wall thickness than the inner sleeve 66, and its ends 75 and 76 are chamfered as illustrated. Intermediate the slots 73 and 74 in the sleeve 67 are thickened portions that dene parallel axially extending ribs 78 that are adapted to :bear against the inner wall of the well casing 11.

Communication between the bore of the tubular member 4() and the inner circumferential wall of the flexible sleeve 57 is provided by a plurality of ports 79 through the tube 40 adjacent the upper end of the sleeve 57, and a similar group of radial yopenings 80 adjacent the bottom end of the sleeve 57. Fluid within the bridge plug has access to the entire inner surface of the flexible sleeve 57 which acts as a diaphragm in retaining the pressurized fluid. A seal is effected between the bead 58 and the adjacent shoulder 59 `of the collar `60 at the upper end. Similarly, at the bottom end of the sleeve 57, it is sealed by the engagement of the bead 62 with the shoulder 63 of the collar `64. The higher the internal pressure, the -greater force there will be for urging the ends of the sleeve 57 into engagement with its adjacent shoulders to increase the sealing elfect. Also, this urges the collars 60 and 64 inwardly with respect to the sleeve 67 so that the elements are securely clamped together. Consequently, there is zero clearance at the ends of the split sleeves 66 and 67 as the collars 60 and 64 are forced against the ends of the split sleeves. This means that there is no possibility of a gap through which the elastomeric sleeve 57 could extrude at the ends of the split sleeves.

The sleeve 67, through its ribs 78, frictionally engages the well casing as the bridge plug moves through it, thereby acting as a drag means for the .bridge plug. Upon generation of an internal pressure, the sleeves 66 and 67 can be expanded by virtue of their slotted construction. The outer ribs 78 of the sleeve 67 provide segments that can securely engage the well casing to lock the bridge plug in position. Very high forces can be applied to the interior of the elastomeric sleeve 57, but it cannot extrude through the slots in the metal sleeves 66 and 67 because these slots are staggered and provide no passageway for the material of the sleeve 57. Tremendous frictional holding forces can be generated in this manner, regardless of the nature of the cavity surface adjacent the lock. Nevertheless, the frictional lock necessarily will be released when the internal pressure is removed, so that it is always possible to retrieve the plug lfrom the well.

The arrangement of the two sets of slots in the sleeves extending inwardly from their outer ends permits a relatively large degree of radial expansion and contraction, allowing the assembly 56 to frictionally grip well surfaces of different diameters. The ability to expand and contract is enhanced -by the manufacturing process for the sleeves 66 and 67 in which these sleeves are machined to substantially the middle diameter that will Ibe encountered in service. The sleeve then is expanded to its maximum dimension during the time of heat treatment. This spreads the slots in the sleeve, as shown in FIGURE 6 for the slots 73 and 74 in the sleeve 67. As a result, the anchoring device is given a wide range in radial dimension, permitting the sleeves to be enlarged or reduced in diameter considerably when the occasion demands. They can be contracted until the outer edge portions of the slots are in abutment, such as to the position of FIGURE 7, While still being expansible to a large diameter to frictionally engage a larger cavity in the well.

In normal usage, the sleeves 66 and 67 will be compressed slightly when the bridge plug 10 is inserted into the well casing 11. Also, the elastomeric sleeve 57 is molded to its largest diameter so that it, too, is reduced in size to t into the hole. The resulting outward force on the well casing, as the members 57, 66 and 67 try to spring radially outwardly, gives the frictional drag as the plug 10 is moved through the well. Most of the drag force comes from the outer split sleeve 67 because of its heavier construction.

At its lower end, the tube 40 threads into an additional tubular member 82, being sealed at this connection -hy an O-ring 83. The tubular member 82 is sealed relative to the collar 64 by an additional O-ring 84. The tube S2 is circumscribed by an elastomeric collar 85 and a packing 86, which may be identical to the corresponding members 34 and 29 that lit around the tube 27. The packing 86 is provided with a recess 87 at its bottom end, and is divergent downwardly to engage the well casing 11 and resist pressures from below. A short sleeve 88 is received in the recess 87, supporting the packing 86 in position. At its upper end, the collar 85 terminates at a shoulder 89 on the tube 82 adjacent also a ring 90 that is threaded onto the tube 82. The interior of the packing 86 is sealed around the tube 82 .by an O-ring 91.

A tube 93 connects by screw threads to the bottom end of the member 82, and is similar to the member 16 at the upper end of the bridge plug 10. An additional seal in the lform of O-ring 94 is provided at the connection between the members 93 and 82. At its lower end, the sleeve 93 is joined by screw threads t-o a relatively short sleeve 95, while an O-ring 96 seals between the members 93 and '95. The sleeve 95 includes an upwardly convergent frustoconical surface 98. The latter acts as a seat for a floating valve member 99 that is similar to the valve 20. The valve member 99 can slide along the rod 12 relative to which it is sealed by an O-ring 100. The valve memer 99 is biased toward its seat by means of a compression spring 101 that at its upper end bears against a split collar 102. The slots 103 through the collar 102 are formed to allow the sleeve valve 42 to pass when the bridge plug 10 is being assembled.

Beneath the valve member 99, the rod 12 is provided with a radial shoulder 104, below which are radially projecting anges 105 on the rod. These members have tapered surfaces 106 at their -upper ends, which correspond in inclination to the angle of the frustoconical surface 97 on the tubular member 95.

When the bridge plug 10 is being lowered into a well, the parts assume the position illustrated in FIGURES 8A and 8B. Because of the frictional drag of the outer sleeve 67 on the wall of the well casing, the rod 12 moves downwardly relative to the assembly of the tubular elements. The displacement of the rod relative to the outer tubular elements is limited by the depth of the slots 14 as the anges 13 on the rod at the upper end of the plug contact the upper tubular member 15 lat the bottom edges of the slots 14. As a consequence of the downward shifting of the rod 12, the shoulder 51 on the rod reacts `against the shoulders `50 on the radial flanges 47 of the central Valve 42, shifting the valve 42 downwardly relative to the outer sleeve 40 and against the force of the compression spring 54. This movement is suicient to cause the shoulder 51 of the rod to move the central valve 42 downwardly to the position of FIGURE 8A, where the O-ring 44 is below the bottom edge of the tubular member 27. Consequently, the ports 41 are opened so that there is communication between the ini terior of the bridge plug and the zone 107 between the packings 29 and 86 and the interior casing wall. The pressure necessarily will be balanced between the packiags 29 and 86 and the exterior of the bridge plug so that the unit can be moved freely.

Also, as the rod 12 is shifted further downwardly, the

shoulder 23 at the upper portion of the rod engages the` upper edge of the valve 20, moving this valve away from the seat 19. In addition, fluid pressure beneath the lower valve member 99 as the bridge plug 10 is being run in will cause the valve to float upwardly away from its seat 98. Hence, there is open communication through the bridge plug, and there will be no possibility of hydraulic lock to prevent its positioning as desired.

When the unit 10 is at a desired location in the well, it may be left in position by disconnecting at the J-slot at the upper end of the rod, or other attaching means provided. When this is done, the spring 54 forces. the valve 42 upwardly, moving the rod 12 with it. This releases the upper valve 25B so that it can be moved by its spring 25 against the seat 19. Also, in the absence of pressure beneath the plug higher than that above it, the spring 101 will close the valve 99'. The unit then assumes the position of FIGURES 1A and 1B with all the valves closed.

The bridge plug 10 initially is held in position by the resilience of the outer sleeve 67 augmented by the radial force coming from the sleeves o6 and 57 inside it as the ribs 78 frictionally engage the well casing 11. Any pressure differential between the top and the bottom of the plug will cause a pressure load to be added to the resilient force. In other words, the pressure in the plug will force `the diaphragm 57 and hence the outer sleeve 67 outwardly against the well casing, so that the ribs 78 more tightly secure the plug in place. The internal pressure -that produces this gripping force is always equal to or greater than the highest pressure at either end of the plug.

With the rod 12 moved upwardly so that the shoulder 23 releases the valve 20, the internal pressure in the bridge plug will force the valve 2@ against its seat 19. Similarly, the pressure within the bridge plug 10 will hold the lower valve 99 against its seat 98. Hence, the bridge `plug of this invention can be pumped up when pressure is applied by any means above the top valve 20. This may be, for example, by pressurizing against the plug with a parent packer prior to doing a frac or cement job. The top valve will close to trap inside the plug 10 the highest pressure applied across the plug.

One of the advantages of the central valve element 42 provided by this invention is that it presents a piston area that allows internal pressures to bias the valve upwardly toward its closed position. This, in turn, causes the valve 42,' through its shoulder 59 reacting against the shoulder 51 of the rod 12, to hold the rod in the upper position. With the rod 12 held in its upper position, the shoulder 23 on the rod prevents the yupper valve 20 from opening under the inuence of well pressures above it, which would allow it to become sanded so that the top valve 20 would be held down and prevented from closing. If that occurred, the pressure inside the plug could not be trapped.

The rod 12 provides a pressure area by which pressures in the well above the tool can move the rod downwardly in the absence of the holding force in the opposite direction provided by the valve 42. In other words, pressure above the plug produces a reaction against the top end of the rod 12 that normally would force the rod toward a lower position to where the elements 13 are stopped against the bottoms of the slots 14. Such pressures, therefore, would cause the shoulder 23 of the rod to react against the upper valve 20, shifting the upper valve downwardly to open it and hence allow sand and other foreign matter to enter the plug, which could cause it to malfunction. However, pressures within the plug can counteract the pressures above it to prevent this f downward movement of the rod 12. This is because the bottom end of the valve 42 provides a pressure area against which iluid pressure can react. When the valve 42 is closed, pressurized fluid in the plug has accesss to the entire bottom area of the valve 42, but the shoulder 43 is blocked from the top side because it is sealed off by the O-rings 44 and 4S. Therefore, there is a greater bottom area against which the iluid can react than is the exposed top area of the valve. This greater bottom valve area, which is the equivalent of the area of the shoulder 43, results in a net upward force on the valve 42. This area differential is made to be greater than the area of the cross-section of the rod through the plug so that there is more force upwardly on the valve than there is downwardly on the rod from equivalent pressures. Hence, the valve 42 is held closed by the internal pressure as well as the spring 53 and, through its shoulder 50, holds the rod in its raised position relative to the tubular body against pressures from above. As noted above, therefore, this assures that the rod does not move downwardly to open the upper valve 20 and, as a result, the interior of the bridge plug remains closed.

With the bridge plug internally pressurized, high pressures can be withstood both from above and from below without the upper and lower valves being opened. In fact, it will withstand pressures from above as great as the pressure sealed within it before the upper valve 20 will be opened. This is because the valve 20 presents as much area inside the bridge plug against which the fluid reacts for urging the valve closed as there is area on the upper side against which pressure `above the bridge plug can react. Also, there is the pressure area on the valve 42 holding the rod up that more than counteracts the rodfcross-sectional area that allowswell pressures to urge it downwardly. With the areas being balanced in this manner, it will require a pressure above the bridge plug greater than the internal pressure before the valve 2i) will be opened.

At the lower end of the bridge plug, the internal pressure urges the valve 99 against its seat, resisting well pressures that would open this valve. The areas of the valve 99 above and below its seat are equal, so that it is balanced as far as direct forces on it are concerned, and well pressures must be large to unseat the lower valve.

As the bridge plug 10 is constructed, the total pressure area from below includes the etlective diameter of the rod 12 as well as the exposed area of the valve 99. On the inside of the bridge plug, the rod area cannot be used by the uid in urging the valve to the closed position. Therefore, pressure beneath the bridge plug can cause the valve 99 to open when it is slightly below the internal pressure of the bridge plug. The exact proportion of the pressure beneath the bridge plug to that inside which will open the valve 99 depends upon the proportioning of the parts, which will, in turn, be governed by the design of the individual unit and the type of well for which it is intended. In all instances, however, the bridge plug will withstand a very substantial pressure from below, as much as normally can be expected under the most extreme conditions. In' a typical example, pressure beneath the bridge plug must reach 75% of that within the bridge plug before the valve 99 will open.

Even in the unlikely event of pressures occurring below the plug sucient to open the lower valve 99, the plug 10 will not become sanded nor will it slip its position. The higher pressure entering the plug would simply force the split sleeve 67 more rmly against the well casing so that the frictional holding force would be increased. Also, the sand is heavier than the uid in the well and will not be forced upwardly into the plug from pressure beneath it. Hence, there is no danger of sanding from the occurrence of high pressures below the plug that would open the valve 99.

When the bridge plug is to be moved, the rod 12 first is shifted downwardly relative to the tubing string. This causes the shoulder 51 of the rod to open the central valve 42 as the O-ring 44 is shifted below the bottom edge of the member 27 and the ports 41 are exposed. With the valve 42 open, the pressure is equalized between the interior of the tubing string and the zone 107 on its exterior between the packings 29 and 86. The lock 56 is released as the pressure on either side of it are eqnalized. Also, with the valve 42 open, pressures can vent through the valve ports 41 from either above or below the bridge plug, depending on which is higher. In other words, a pathway is provided from the interior of the tubing string through the ports 41 to the zone 107 and from there past the packing at the low pressure end. The packings 29 and 86, of course, will hold pressure only from their outside ends because of their cup-shaped configurations. As a result, the entire assembly can be moved freely in the well as the rod initially opens the central valve 42. After the pressures are equalized by the opening of the Valve 42, the rod 12 can be moved down further to open the top valve 20, moving the parts to the position of FIGURE 8A.

To raise the bridge plug, a subsequent upward pull on the rod 12 will bring the tapered surfaces 106 of the anges 105 at the bottom of the rod into contact with the frustoconical surface 97 at the lower end of the sleeve assembly. Hence, with these surfaces of the rod and sleeve in contact, the rod and the sleeve assembly can be moved together.

This upward movement of the rod relative to the tubing string to bring the flanges 105 into engagement with the surface 97 causes the rod shoulder 104 to react against the lower valve 99 to open that valve. Also, upon upward movement, any resisting uid will open the upper valve so that again there is an lopen passageway through the bridge plug and the tool lcan be moved in the upward direction.

The construction of the plug of this invention also enables it to give a tattletale signal to indicate its location in the well. Because of this, there can be certainty when the plug has been reached when it comes time to move it within the well. This position-indicating function is made possible by the construction of the head at the upper end of the rod, as shown in FIGURES 10 and 11, as well as the valving arrangement and other components incorporated in the plug.

The head 10S threads onto the top end extension 109 of the rod, with the lower end of the head bottoming against the shoulder 110 on the rod. An automatic I-slot 111 is formed in the circumferential surface of the head. The entrance to the slot is defined by downwardly sloping surfaces 112 and 113 that extend circumferentially in opposite directions from a peak 114 where they meet. The surfaces 112 and 113 at their lower ends define a narrow gap 115 below which is an inclined surface 116 leading to a vertical recess 117. Directly above t-he recess 117 the slot has a surface 118 that slopes upwardly to a short flat area 119 beneath which is a recess 120, the bottom edge 121 of which is higher than the bottom edge 122 of the vertical recess 117.

The lower end of the tool for engaging the head includes a hollow tubular section 123, dimensioned to receive the head 108 within its bore 124. Projecting radially into the bore 124 is a dog 125 having convergent upper and lower ends 126 and 127, respectively. The bottom edge 128 of the tubular section 123 is chamfered to slope inwardly, as illustrated.

When the tubular section 123 is lowered into the well at the bottom end of a tubing string, its first Contact with the bridge plug 10 will be when the dog 125 strikes either of the sloping surfaces 112 or 113. If the dog should hit the peak 114 where the surfaces 112 and 113 join, it will slide off on one side or the other. The dog 125 will progress along the surface 112 or 113 as the member 123 moves further downwardly, being brought to the gap where it is guided by the inclined surface 116 into the vertical recess 117. As the dog moves into the recess 117, it will be stopped short of the bottom edge 122 of the recess. This comes about because of the engagement between the bottom edge 128 of the tubular section 123 and the similarly tapered upper edge 129 of the tubular body of the plug. At this position, therefore,

axial forces are transmitted directly to the tubular body of the bridge plug, and are not imparted to the rod 12.

The dog 125 then is moved upwardly by pulling on the tubular section 123 to bring the dog into contact with the upwardly sloping surface 11S. This guides the dog 125 to the flat surface 119.

Movement of the dog downwardly from this position brings it into engagement with the bottom edge 121 of the recess 120. At that point, the dog can move the rod 12 downwardly for moving the central valve 42 to the Open position, and for also opening the upper valve 20. Upward movement of the dog 125 allows it to retrieve the plug 10 by pulling upwardly on the rod 12 through its engagement with the surface 119.

The dog 12S can be moved out of the slot 111 by giving the member 123 left-hand torque for short downward movement along surface 116 so that the dog can enter the gap 115, and with subsequent upward movement escape from the slot.

The tattletale signal occurs during the time of contact between the lower edge 128 of the tubular section 123 and the upper edge 129 of the member 15 at the top end of the body of the bridge plug. With the tubing string load all transmitted to the body of the bridge plug, the rod will stay in its upper position with the central valve 42 closed. In the event that pressure previously has been trapped in the plug, the anchor 56 will have locked the tubular body of the plug in its position. Hence, there is a signal to the top of the well that the plug has been reached because further downward movement is prevented. On the other hand, if only the resilience of the sleeves of the anchor 56 is holding the plug in position, the plug will move down in the well as the tubing string load is applied to the plug body. This movement is limited, however. The downward shifting of the plug compresses t-he fluid in the well below the plug, so that pressure soon builds up inside the plug. This pressure reacts against the elastomeric sleeve 57, which, in turn, expands the sleeves 66 and 67. In this manner, the anchor 56 locks the plug against further movement in the well. Again, there is a tattletale signal because the plug cannot be moved beyond the limited distance. Consequently, regardless of the condition of the plug, it will lock as the load is applied to the body and a definite indication is transmitted to the surface to establish that the plug has been found.

Even in retrieving the plug, it is possible to check to make certain it has been hooked onto. Left-hand torque and downward movement will cause the dog 125 to move from the area 119 along the surface 113 to the surface 116. Then, with the application of right-hand torque the dog can move down into the recess 117 so that the edges 128 and 129 can be brought into interengagement. Continued downward movement will lock the plug to show that it has not been lost.

It can be observed, therefore, that the device of this invention provides a retrievable bridge plug of improved performance which, nevertheless, is of relatively simple construction. The bridge plug can be made to accomplish any desired function through the operation of its valves by movement of the rod. Also, the bridge plug provides a secure and positive anchoring through expansible sleeve elements that can accommodate a wide range in diameter changes. There are no dogs or other elements incorporated in the unit which could break and prevent removal from the well. The lock accomplished upon internal pressurization is quite strong, and, is noted above,

1 l the unit will withstand pressures both above and below when it is retaining internal pressure.

The foregoing detailed description is to be clearly understood as given by way of illustration and example only, the spirit and scope of this invention being limited solely by the appended claims.

I claim:

1`. A bridge plug comprising:

a body adapted for insertion in a well bore,

said body having spaced ends and a passage means interconnecting said ends,

spaced sealing means on the exterior of said body for engaging an adjacent surface of a well bore and effecting a seal therewith,

a first valve means for controlling uid ow at one end of said passage means,

a second valve means for controlling fluid flow at the opposite end of said passage means,

anchor means on said body intermediate said sealing means, said anchor means including means responsive to an increased pressure in said passage means relative to the pressure eXteriorly of said body intermediate said sealing means for engaging the adjacent surface of a well bore and holding said body therein, and responsive to a decrease in the pressure in said passage means relative to the pressure exteriorly of said body intermediate said sealing means for releasing such a surface,

a third valve means for controlling access between said passage means and the exterior of said body intermediate said sealing means,

whereby said third valve means when closed causes pressure in said passage means to be applied to the exterior of said body intermediate said sealing means for causing release of said anchor means, said third valve means including an area subject to pressure in saidv passage means when said third valve means is closed for exerting a force to hold said third valve means closed,

whereby said pressure resists opening of said third valve means,

and actuating means for operating said first, second and third valve means, said actuating means being engaged by said third valve means when said third valve means is in said closed position for holding said actuating means inoperative through pressure in said passage means.

2. A bridge plug comprising:

a body adaptedv for insertion in a well bore,

said body having spaced ends `and a passage means interconnecting said ends, v

spaced sealing means on the exterior of said body for engaging an adjacent surface of a well bore and effecting a seal therewith,

a first valve means for controlling fluid flow at one end of said passage means,

a second valve means for controlling uid flow at the opposite end of said passage means,

an anchor means on said body intermediate said sealing means,

said anchor means including a fluid-expansible sleeve means, and segmented means on the extrior of said fluid-expansible sleeve means for engagingan adjacent surface of a well bore,

said sleeve means being responsive to an increase in pressure in said passage means relative to the pressure exteriorly of said body intermediate said sealing means for urging said segmented means against said adjacent surface of a well bore for frictionally gripping said adjacent surface and holding said body in said well bore,

said sleeve means being responsive to a decreased pressure in saidpassage means relative to the pressure exteriorly of said body intermediate said sealing means for releasing the force exerted on said segmented means so that said segmented means releases said adjacent surface of a well bore,

a third valve means for controlling access between said passage means and the exterior of said body intermediate said sealing means,

whereby said third valve means when closed causes pressure in said passage means to be applied to said sleeve means for causing said sleeve` means to so urge said segmented means against said adjacent surface of a well bore, and

said third valve means when open causes pressure in said passage means Vto be applied to the exterior of said body intermediate said sealing means for causing release of said adjacent surface by said segmented means,

said third valve means including an area subject to pressure in said passage means when said third valve means is closed for exerting a force to hold said third valve means closed,

whereby said pressure resists opening of said third' valve means,

and actuating means for operating said first, second and third valve means,

said actuating means being engaged: by said third valve means when said third valve means is in said closed position for holding said actuating means inoperative through pressure in said passage means.

3. A bridge plug comprising a tubular means adapted to be received in a well,

rod means extending into said tubular means,

a duality of spaced packings on the exterior of said tubular means adapted to sealingly engage the wall of aweil,

an anchor means carried by said tubular means intermediate said packings,

said anchor means including drag means for normally kproviding a resistance to movement of said tubular means in a well, and including means responsive to uid pressure in said tubular means for exerting an outward force and frictionally gripping the adjacent surface of a well and holding said tubular means therein,

a first val-ve mea-ns at the top portion of said` tubular means for controlling access to said tubular means at said topV portion,

a second valve means at the bottom portion of said tubular means for controlling access to said `tubular means at said bottom portion,

said first and second valve means including means responsive to pressure differentials for urging each of said valve means to a closed position in response to pressures inwardly of said tubular means and to any open position in response t0 pressuresl exteriorly of said. tubular means at said top and bottom ends of said tubular means respectively, and a third valve means located intermediate said packings for access between the interior of said tubular means and the exterior thereof at said intermediate location,

said third valve means being movable to any open position in response to selective relative movement between said rod means and said tubular means, said third valve means including a pressure area responsive to pressure in said tubular means for holding said third valve means in a closed position.

4. A retrievable bridgev plug for a well comprising a tubular body adapted to enter a well, a duality of spaced sealing members on the exterior of said body for sealingly engaging the wall of a well,

a friction drag and anchor means carried by said body a first valve means at the top portion of said body for controlling access to the interior of said body at said top portion,

a second valve means at the bottom portion of said body for controlling access to the interior of said body at said bottom portion,

said first and second valve means being urged to a closed position by pressures within said body, and being urged to an open position by external pressures at the top and bottom of said body respectively,

third valve means intermediate said sealing members for controlling access between the interior and exterior of said body at a location between said sealing members, and

rod means extending into said body,

said rod means having a first abutment means for opening said first valve means upon downward movement of said rod means relative to said body through a predetermined distance, a second abutment means for opening said second valve means upon upward movement of said rod means relative to said body, and having a third abutment means for opening said third valve means upon downward movement of said rod means relative to `said body through an increment less than said predetermined distance for opening said first valve.

A retrievable bridge plug for a well comprising tubular body adapted to enter a well,

duality of spaced sealing members on the exterior of said body for sealing engaging the wall of a well,

a friction drag and anchor means carried by said body for providing a resistance to movement of said body in a well, K

said drag and anchor means including a means intermediate said sealing members which is radially expansible in response to iiuid pressures in said body for frictionally gripping the wall of a -well and holding said body axially ixed therein, first valve means at the top portion of said body for controlling access to the interior of said body at said top portion, second valve means at the bottom portion of said body for controlling access to the interior of said body at said bottom portion,

' said iirst and second valve means being urged to a closed position by pressures within said body, and being urged to an open position by external pressures at the top and bottom of said body respectively,

third valve means intermediate said sealing members for controlling accessbetween the interior and exterior of said body at a location between said sealing members, and

rod means extending into said body, said rod means having a iirst abutment means for opening said iirst valve means upon downward movement of said rod means relative to said body through -a predetermined distance, a second abutment means for opening said second valve means upon upward movement of said rod means relative to said body, and having a third abutment means for opening said third valve means upon downward movement of said rod means relative to said body through an increment less than said predetermined distance for opening said first valve,

said third valve means being movable upwardly relative to said body to a closed position, and including pressure area means capable of being reacted against by iiuid pressure within said body when said third valve means is in said closed position for biasing said third valve means upwardly relative to said body to maintain said third valve means in said closed position, for causing said third valve means through said third abutment means to hold said rod means upward relative to said body for preventing the opening of said first valve means by said iirst abutment means.

A retrievable bridge plug for a well comprising a tubular body adapted to enter a well,

a friction drag and anchor means carried by said body for providing a resistance to movement of said body in a well,

said friction drag and anchor means including an expansible sleeve of elastomeric material circumscribing said tubular body intermediate said sealing members,

said tubular body having openings therethrough providing communication between the interior of said tubular body and the interior of said elastomeric sleeve, and segmented means circumscribing said elastomeric sleeve,

whereby pressure in said tubular body applied through said opening to the interior of said elastomeric sleeve can cause expansion of said segmented means for causing said segmented means to frictionally grip the Wall of a well and holding said body axially iixed therein,

a -tirst valve means at the top portion of said body for a third valve means intermediate said sealing members for controlling access between the interior and exterior of said body at a location between said sealing members,

whereby when said third valve means is open pressure from the interior of said body is applied exteriorly thereof intermediate said sealing members so that said sleeve and segmented means will release the wall of a well gripped thereby,

and a rod means extending into said body,

said rod means having a iirst abutment means for opening said iirst valve means upon downward movement of said rod means relative to said body through a predetermined distance,

a second abutment means for opening said second valve means upon upward movement of said rod means relative to said body, and

having a third abutment means for opening said third valve means upon downward movement of said rod means relative to said body through l an increment less than said predetermined distance for opening said first valve.

7. A bridge plug comprising a tubular means adapted to be received in a well,

rod means extending into said tubular means,

a duality of spaced packings on the exterior of said tubular means adapted to sealingly engage the wall of a well,

an anchor means carried by said tubular means intermediate said packings,

said anchor means including an elastomeric member expansible outwardly in the radialv direction in response to fluid pressure thereon,

said elastomeric member being in communication with the interior of said tubular means for being subjected to fluid pressures therefrom, and a segmented means outwardly of said elas tomeric member and movable outwardly by said elastomeric member against the adjacent surface of a well casing,

said segmented means having outer surface portions for frictionally engaging said well casing and providing a resistance to movementl of` said tubular means therethrough, said surface portions frictionally locking said'tubular means in said well casing when expanded outwardly by uid pressure exerted on`said elastomeric member,

a first valve means at the top portion of said tubular means for controlling access to said tubular means at saidY top portion,

a second valve means at the bottom portion of said tubular means for controlling access to said tubular means at said bottom portion,

said first and second valve means including means responsive to pressure differentials for urging each of saidvalve means to a closed position in response to pressures inwardly of said tubular means and to an open position in response to pressures exteriorly of said tubular means at said top and bottom ends of said tubular means respectively,

a third val-ve means located'. intermediate said packings for access between the interior of said' tubular means and the exterior. thereof at said intermediate location,

said first, second and third valve means being selectively movable to an `open position in response tol selective relative movement between said rod means and said tubular means,

said third valve means having a surface sealed with respect ,to said body when said third valve means is closed so that the remainder of said third valve means presents surface portions against which pressurized iiuid in said tubular means react to hold said third valve means in said closed position, and

resilient means biasing said. third valve means to said closed' position.

8. A retrievable bridge plug comprising a tubular body adapted to enter a well,

a rod extending into said body,

a first valve at the upper portion of said body slidahly receiving said rod and axially movable relative thereto,

a first valve seat in said body above said first valve engageable by said first valve for sealing the interior of said body from above.,

a second valve at the bottom por-tion of said body slidahly receiving said rod and axially movable relative thereto,

- a second valve seat Vin said body beneath said second valve for engagement by said secondvalve for sealing the interior of said body from below,

16 a duality of spaced packing elements circumscribing said body and engageable with the wall of a well,

each of said packing elements being flared outwardly to resist Iand sealv with respect to fiuid pressures from the adjacent end of said body, an anchor means c arried by said body,

said anchor means being operable by pressures within said body for securing said body to a well within which said body is` located and axially locking Asaid bodytherein,

said anchor means being intermediate said packing elements, a third valve in said body intermediate said packing elements and adjacent said anchor means,

said body having passage meansV between the interior thereof and the exterior thereof intermediate said packing elements,

said passage means being closed when said third valve is in an upward position and` open when said third valve is in a downward position,

resilient means biasing said third valve upwardly to said closed position wherein said passage means are closed,

a first shoulder on said rod engageable with said first valve for moving said first valve downwardly away from said first valve seat for opening said first valve upon relative movement of said rod through a predetermined distance downwardly with respect to said body,

a second shoulder on said rod for engaging said second valve and moving said second valve upwardly away from said second valve seattfor opening said second valve upon relative movement of said rod upwardly with respect to said body,

a third shoulder on said rod in engagement with said third val-ve, for moving said third valve downwardly to an open position upon movement of said rod downwardly with respect to said body through an increment less than said predetermined distance,

whereby upon movement of said rod downwardly with respect to said body said third valve is opened prior to the opening of said first valve,

and abutment means on said rod forperrnitting said rod to push said body into a well casing and to pull said body therefrom.

9. A retrievable bridge plug comprising a tubular body adapted to enter a well,

a rod extending into said body,

a first valve at the upper portion of said body slidahly receiving said rod and axially movable relative thereto,

a first valve seatin said body above said first valve engageable by said first valve for sealing the interior of said body from above,

a second valve at the bottomportion of said body slidably receiving said rod and axially movable relative thereto,

a second valve seat in said. body beneath said second valve for engagement by said second valve for sealing the interior of said body from below,

a duality of spaced packing elements circumscribing said body-and engageable with the wall of a well,

each of said packing elements being dared outwardly to resist and seal with respect to fluid pressures from the adjacent end of said body, an anchor means carried by said body,

said anchor means being operable by pressures within said body for securing said body to a well within which said body is located and axially locking said body therein,

said anchor means being intermediate said Y packing elements,

a third valve-in said body intermediate said packing elements and adjacent said anchor means,

said body having passage means between the interior thereof and the exterior thereof intermediate said packing elements,

said passage means being closed when said third valve is in an upward position and open when said third valve is in a downward position,

resilient means biasing said third valve upwardly to said closed position wherein said passage means are closed,

a first shoulder on said rod engageable with said first valve for moving said first valve downwardly away from saidfirst valve seat for opening said first valve upon relative movement of said rod through a predetermined distance downwardly with respect to said body,

a second shoulder ony said rod for engaging said second valve and moving said second valve upwardly away from said second valve seat for open-ing said second valve upon relative movement of said rod upwardly with respect to said body,

a third shoulder on said rod in engagement with said third valve for moving said third valve downwardly to an open position upon movement of said rod downwardly with respect to said body through an increment less than said predetermined distance,

whereby upon movement of said rod downwardly with respect to said body said third valve is opened prior to the opening of said first valve, said third valve when in said closed position presenting a pressure area against which internal fiuid pressure can react urging said third valve upwardly for holding said third valve in said closed position,

whereby said third valve through said third shoulder holds said rod upwardly relative to said body and said first shoulder is prevented from opening said first valve,

and abutment means on said rod for permitting said rod to push said body into a well casing and to pull said body therefrom.

10. A retrievable bridge plug comprising a tubular body adapted to enter a well,

a rod extending into said body,

a first valve at the upper portion of said body slidably receiving said rod :and axially movable relative theret0,

a first valve seat in said body above said first valve engageable by said first valve for sealing the interior of said body from above,

a second valve at the bottom portion of said body slidably receiving said rod and axially movable relative thereto, v a second valve seat in said body beneath said second valve for engagement by said second valve for sealing the interior of said body from below, a duality of spaced packing elements circumscribing said body and engageable with the wall of a well,

each of said packing elements beign ared outwardly to resist and seal with respect to uid pressures from the adjacent end of said body, an anchor means carried by said body,

said anchor means being intermediate said 'packing elements, said anchor means including an elastomeric sleeve Yfor frictionally engaging a well casing and procircumscribing said body and sealed with 're- 18 vidng a resistance to movement therethrough, said gripping means including segment-s for allowing expansion of said gripping means in response to pressurized fluid reacting thereon through said elastomeric sleeve,

a third valve in said body intermediate said packing elements and adjacent said anchor means,

said body having passage means between the interior thereof and the exterior thereof intermediate said packing elements,

said third valve being movable upwardly to a first position closing said passage means and downwardly to a second position opening said passage means, said body having a surface sealingly engaged by said third valve when said third valve is in said upward position to block upwardly directed surface portions of said third valve from pressurized fluid within said body,

whereby pressurized fiuid in said body urges said third valve upwardly to hold said third valve'in said upward position, resilient means biasing said third valve upwardly to said closed position `wherein said passage means are closed,

a first shoulder on said rod engageable with said first valve `for moving said first valve downwardly away from said rst valve seat for opening said first valve upon relative movement of said rod through a predetermined distance downwardly with respect to said body,

a second shoulder on said rod for engaging said second valve and moving said second valve" upwardly away from said second valve seat for opening said second valve upon relative movement'of said rod upwardly with res-pectto said body,

a third shoulder on said rod in engagement with said third valve for moving said third valve downwardly to an open position upon movement of said rod downwardly with'respect to said body through an increment less than said predetermined distance,

whereby upon movement of said rod downwardly with respect to said body said third valve is opened prior to the opening of said first valve, and abutment means on said rod for permitting said rod to push said body into a well' casing and to pull said body therefrom.

11. A retrievable bridge plug comprising a tubular body,

:a rod means extending into said body `from the-upper end 'of said body,

a first pressure responsive valve means at the top portion of said body for controlling access to the interior thereof,

a second pressure responsive valve means at the bottom portion of said body for controlling-access to the interior thereof,

said first valve means being movable to a closed position in response to pressure beneath said first valve means,

said second valve means being movable to a closed position in response to pressure above said second valve means,

a third valve means intermediate said first and second valve means for controlling access' between'the interior and exterior of said body at said intermediate location,

said rod means and said third valve means havl ing cooperative means for opening said third valve meansupon selective movement of said rod means relative to said body, said rod means and body having cooperativey abutment means for moving said body in response to movement of said rod means, i V pressure-responsive anchor means carried by said body 19 for engaging a well casing and` locking said body thereto in response to pressure within said body, and

means for engaging said rod means for effecting movement of said rod,

said last mentioned means including means for engaging said body while simultaneously disengaging said rod,

for providing a signal that said body has been encountered in a well through resistance to movement to provide by said pressureresponsive anchor means.

12. A retrievable bridge plug comprising a tubular body, l

a rod extending into the upper end of said body,

said rod and body including Acooperatively abutment means for moving said body in response to movement of said rod,

said abutment means permitting limited relative movement of said rod relative to said body,

a first valve means at the top portion of said body for blocking access to said top portion when said first valve means is in a closed position,

aisecond valve means at the bottom portion of said body for blocking access to said body when said second valve means is closed,

said body having aperture means providing communication with the exterior thereof intermediate said first and second valve means,

a third valve means for controlling said aperture means,

a pressure-responsive anchor meansfon said body intermediate said first and second valve means,

a first seal means on the exterior of said body above said aperture means and anchor means, 4

a second seal means on the exterior of said body below said aperture means and anchor means,

said rod and said valve means including interengageable surfaces for selectively opening said valve'means upon relative movementof said rod and said body,

and an actuating tool for moving said body through engagement with said rod,

said actuating tool having a dog,

said rod having a head portion including a slot means therein for receiving said dog,

said dog being engageable with said head in saidl slot means for effecting movement of said rod, v

said slot means including fa portioniinto which said dog can enter where said head provides no obstruction to downward movement of said actuating tool,

Y said actuating tool having a surface brought into engagement with said body upon downward movement of said actuating tool when said dog is in saidportion,

whereby said body through said anchor means provides an obstruction to downward movement of said actuating tool to provide a signalindicating that said body has been encountered in a well.

13. A retrievable bridge plug comprising v a tubular body,

a rod extending into the upper end of said body,

said rod and body includingcooperative abutment means `for moving said body, in response to movement of `said rod,

said abutment means permitting limited relative movement of said rod relative to said body,

a first valve means at the top portion of said body for blocking access to said top portion when said first valve means is in a closed position,

a second valve means at the `bottom portion of said body for blocking access to said body when said second valve 4means is closed,

said body having aperture means providing communication with the exterior thereof intermediate said first and second valve means, a third valve means for controlling said aperture means, a pressure-responsive anchor means on said body intermediate said first and second valve means, l

said anchor means including a diaphragm communicating with the interior of said body for expansion outwardly in response to pressure in said body, and segmented means on the exterior of said diaphragm for engaging the wall of a well casing and frictionally gripping the same, a first seal means on the exterior of said body above said aperture means and anchor means, a second seal means on the exterior of said body below said aperture'means and anchor means,

said rod and said Valve means including interengageable surfaces for selectively opening said valve means upon relative movement of said rod and said body, and an actuating tool -for moving said body through engagement with said rod,

said actuating tool having a dog, said rod Ahaving a head portion including a slot means therein for receiving said dog,

said dog being engageable with said head in said slot means for effecting movement of said rod, said slot means including a portion into which said dog can enter where said head provides no obstruction to downward movement of said actuating tool,

said actuating tool having a surface brought into` engagement with said body lupon downward movement of said actuating tool when said dog is in said portion,

whereby said body through said anchor means provides an obstruction to downward movement of said actuating tool to provide a signal indicating that said body has been encountered in a well. 14. A bridge plug comprising 1a tubular means adapted to 'be received in a well,

said tubular means having an upper end and a lower end, a member extending into said tubular means through said upper end thereof,

said member and said tubular means having interengageable abutment means for permitting said member to effect movement of said tubular means into and out of a Well,

said abutment means including means for allowing limited movement of said member relative to said tubular means, first fiow control means for controlling y fiuid flow through said upper end of said tubular means, second flow control means fory controlling fluid flow through said lower end of said tubular means, third fiow control means for controlling fluid flow between the interior and exterior of said tubular means at a location intermediate said first and said second ow `control means, pressure-responsive anchor means at said location,

said anchor means being in communication with said interior and exterior of said tubular means, and being operable by pressure in said tubular means for engaging an adjacent surface of a well and holding said ltubular means therein,

and seal means exteriorly of said tubular means on either side of said intermediate location,

said seal means being engageable with :adjacent well surfaces for effecting a seal therewith,

said member including means for opening said ow control means upon said limited movement thereof relative to said tubular means,

said third flow control means including means operable upon by pressurized uid for maintaining said third ow control means in .a closed position and preventing said member from opening said iirst llow control means.

15. A packer for use in a well bore containing uid comprising a body member having spaced-apart end portions, a passage therethrough, and port means between said passage and the exterior of said body member, said port means being disposed intermediate of said ends, packing means on said body member disposed above and below said port means for preventing uid ow between the exterior of said body member and the wall of a well bore, pressure-responsive drag and anchor means on said body member disposed intermediate of said packing means for engaging the wall of a well bore with sucient force to provide frictional drag with the wall of a well bore and responsive to applied hydraulic pressure for engaging the wall of a well bore with sulcient force to provide an anchoring with respect to `the wall of a well bore, and selectively operable valve means for coupling pressure in the well bore to said drag and anchor means, said valve means being operable in one position for passing fluid through said passage and through said port means and being operable in another position for closing said port means and at least one end of said passage to permit application of hydraulic pressure to said drag and anchor means, said valve means including a pressure area responsive to pressure in said passage for holding said valve means in said position where said valve means and said one end of said passage are closed.

16. A packer for use in a well bore containing Huid comprising a body member having a passage therethrough, spaced packing means on said body member for preventing uid flow between the exterior of said body member and the wall of a well bore, port means between said passage and the exterior of said body member, drag and anchor means on said body member disposed intermediate of said packing means for frictionally engaging the wall of a well bore and responsive to uid pressure for anchoringly engaging said packer with respect to the wall of a well bore, and selectively operable valve means for admitting fluid pressure in the Well bore to said drag and anchor means, said valve means being movable between one position for admitting hydrostatic pressure through said passage and through said port means and being movable to another position where said port means is closed and said pressure is admitted to said drag and anchor means, said valve means including a pressure area responsive to fluid pressure in said passage for holding said valve means in said position where said port means is closed.

17. A packer for use in a well bore containing fluid comprising a body member having spaced-apart end portions, a passage therethrough, and port means between said passage and the exterior of said body member, said port means being disposed intermediate of said ends, packing means on said body member disposed above and below said port means for preventing fluid ow between the exterior of said body member and the wall of a well bore, pressure-responsive anchor means on said body member disposed intermediate of said packing means and responsive to applied hydraulic pressure for engaging the wall of a well bore with sufficient force to provide an anchoring with respect to the wall of a well bore, selectively operable valve means for coupling pressure in the well bore to said anchor means including a movable control means and rst and second valve means, said rst valve means being operable in one position of said control means for passing iluid through said passage, said second valve means being operable in said one position for passing uid through said port means, said rst valve means being operable in another position of said control means for closing said passage, said second valve-means being operable in said other position for closing said port means, said second valve means having pressure areas operative in said other position to maintain said control means in said other position when pressure is applied.

18. A packer for use in a well bore containing uid comprising a body member having spaced-apart end yportions, a passage therethrough, and port means between said passage and the exterior of said body member, said port means' disposed intermediate of said ends, packing means on said body member disposed above and below said port means for preventing fluid ow between the exterior of said body member and the wall of a well bore, pressure-responsive anchor means on said -body member disposed intermedi-ate of said packing means and responsive to applied pressure for engaging the wall of a wel) bore with suicient force to provide an anchoring with respect to the wall of a well bore, means for selectively operating said anchor means including control means extending through said passage and movable longitudinally therein, upper and lower valve members movably mounted on said control means and normally biased to move away from one another to closed positions on upper and lower valve seats,v and a port valve member operatively associated with said control means so as to move conjoinftly therewith when said control means moves downwardly, said port valve member having areas responsive to pressure to maintain said port valve member in a closed position to prevent such conjoint movement.

19. A packer for use in a well bore containing uid comprising a body member having -spaced-apart end portions, a passage therethrough, and por-t means between said passage and the exterior of said body member, said port means being disposed intermediate of said ends, packing means on said body member disposed above arid below said port means for preventing uid ow between the exterior of said body member and the wall of a well bore, pressure-responsive anchor means on said body member disposed intermediate of said packing means and responsive to.A applied hydraulic pressure for engaging the wall of a well bore with sucient force to provide an anchoring with respect to the wa-ll of a well bore, passage valve means including upper and lower valve members slidably mounted on a movable control member for'selectively opening and closing said passage upon movement of said control member and including biasing means for normally closing said valve means, a sleeve valve member slidably mounted in said passage of said body member for opening and closing said port means, said sleeve member and body member having differential areas whereby pressure in said passage normally maintains said port means closed o, and means on said control member cooperating, upon movement of said control member in one direction, with said sleeve valve member for opening said port means and cooperating with said sleeve valve member, when said port means are closed, for preventing movement of said contnol member in said one direction in response to pressure within said passage.

20. A packer for use in a well bore containing uid comprising a body member having a passage therethrough, packing means on said body member for pre/venting fluid flow between the exterior of said body member and the wall of a well bore, port means providing communication between said passage and the exterior of said body member, drag and anchor means on said -body member disposed intermediate of said packing means for frictionally engaging the wall of a well bore and responsive to uid pressure for anchoringly engaging said packer with respect to the wall of a well bore, and selectively operable valve means for admitting liuid pressure in the well bore to said drag and anchor means, said valve means being movable between one position for admitting fluid through said r23- 24y passage and being movable to another position for clos- References Cited' ing oneiend of said passage and said port means so that UNITED STATES PATENTS fluid pressure can be admitted to said drag and anchor means, said valve means including a pressure area retgt al' --v- Sponsive to pressure 1n said passage for holding said 5 2:990883 ,H1961 Lewis 166 120 val-ve means in said position where said port means is closed. JAMES A. LEPPINK, Primm), Examiner. 

16. A PACKER FOR USE IN A WELL BORE CONTAINING FLUID COMPRISING A BODY MEMBER HAVING A PASSAGE THERETHROUGH, SPACED PACKING MEANS ON SAID BODY MEMBER FOR PREVENTING FLUID FLOW BETWEEN THE EXTERIOR OF SAID BODY MEMBER AND THE WALL OF A WELL BORE, PORT MEANS BETWEEN SAID PASSAGE AND THE EXTERIOR OF SAID BODY MEMBER, DRAG AND ANCHOR MEANS ON SAID BODY MEMBER DISPOSED INTERMEDIATE OF SAID PACKING MEANS FOR FRICTIONALLY ENGAGING THE WALL OF A WELL BORE AND RESPONSIVE TO FLUID PRESSURE FOR ANCHORINGLY ENGAGING SAID PACKER WITH RESPECT TO THE WALL OF A WELL BORE, AND SELECTIVELY OPERABLE VALVE MEANS FOR ADMITTING FLUID PRESSURE IN THE WELL BORE TO SAID DRAG AND ANCHOR MEANS, SAID VALVE MEANS BEING MOVABLE BETWEEN ONE POSITION FOR ADMITTING HYDROSTATIC PRESSURE THROUGH SAID PASSAGE AND THROUGH SAID PORT MEANS AND BEING MOVABLE TO ANOTHER POSITION WHERE SAID PORT MEANS IS CLOSED AND SAID PRESSURE IS ADMITTED TO SAID DRAG AND ANCHOR MEANS, SAID VALVE MEANS INCLUDING A PRESSURE AREA RESPONSIVE TO FLUID PRESSURE IN SAID PASSAGE FOR HOLDING SAID VALVE MEANS IN SAID POSITION WHERE SAID PORT MEANS IS CLOSED. 